<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Responsive Layout Example</title>
  <style>
    /* PC 端样式 */
    .container {
      max-width: 960px;
      margin: 0 auto;
    }
    .header {
      height: 80px;
      background-color: #ccc;
    }
    .main {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
    }
    .card {
      width: calc(33.33% - 20px);
      margin-bottom: 20px;
      background-color: #f5f5f5;
      box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    }
    .card img {
      max-width: 100%;
    }
    
    /* 移动端样式 */
    @media screen and (max-width: 767px) {
      .container {
        max-width: 100%;
        padding: 0 10px;
      }
      .header {
        height: 50px;
      }
      .card {
        width: calc(50% - 10px);
      }
    }
  </style>
</head>
<body>
  <div class="container">
    <header class="header"></header>
    <main class="main">
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
      <div class="card"><img src="https://lmg.jj20.com/up/allimg/tp09/210Z6134K91506-0-lp.jpg"></div>
    </main>
  </div>
</body>
</html>
